Process for rendering water-insoluble melamine-formaldehyde resins watersoluble



United States Patent PROCESS FOR RENDERKNG WATERJNSOLUBLE MELAMlNE-FORMALDEHYDE RESl'NS WATER- SOLUBLE William J. van Loo, .llri, Middlesex, Ni, and Jason M. Salsbury, fitamford, Conn, assignors to American Cyanamid Company, Stamford, Conn, a corporation of Maine NoDr-awing. Original application May 6, 1959, Ser. No. 811,256, now Patent No. 3,087,837,, dated Apr. 30, 1963. Divided. and this. application Apr. 10, 1962, Ser. No. 186,357

3 Claims. (Cl. Mil-29.4)

This application is a divisional application of Serial No. 811,256, filed May 6, 1959, now US. Patent No. 3,087,837.

The present invention relates to novel textile finishing resins and to the processes for treating textiles with such' resins. cellulosic textile materialswith normally water-insoluble melamineresins to impart wrinkle recovery and shrinkage control thereto.

As is well known in the textile finishingfield, resins employedfor the creascproofing or the impartation of wrinkle recovery to cellulosic textile materials are almost without exception water-soluble ,in nature. This is particularly true in so far asthe use of aminoplast finishing resins. are concerned- Water-solubility is an important characteristicof such-resins, in that application. techniques are significantly less difficult and lessexpensive. Thus, for example, the use of. resins soluble only in a non.- aqueous s0lvent,.present. solvent recovery and odor problems, and in addition thepresence, of solvent frequently adversely affects the hand of.the finished fabrics A number of finishes of the water-soluble resin type have been employed to impart wrinkle recovery and shrinkage control to cellulosic textile fabrics. Most successfulof these resin finishesare the urea-formaldehyde, ethylene urea-formaldehyde and certain melamine-formaldehyde resin types. Each of these resins, however; possesses certain deficiencies which tend to restrict its use in certain applications.

The Water-soluble urea-formaldehyde resin type, the first to be commercially successful for textile use, when applied to cellulosic fabric, causes considerable tensile strength loss when ironedor scorched following. chlorine bleaching. In addition, high concentrations of the resin are required to produce desirable improvement in wrinkle recovery, which further intensifies the deleterious etfects. of chlorine retention.

Thewater-soluble melamine-formaldehyde type resins impart much higher wrinklerecovery to cellulosic fabric at aconsiderably lower concentration of resin solids, than in the case of urea-formaldehyde resins. In addition, they do not-cause tensile strength losses on treated fabric when scorched following chlorine bleaching. They also possess considerably improved durability to usual washing and bleaching operations over the urea type resin. Certain of these resins, however, possess the deficiency of being discolored bychlorine bleaching, which tends to restrict their use on white fabrics. In addition, these and the other resin types mentioned herein tend to firm the hand or stiffen the fabric treated therewith, which is undesirable in many applications, particularly where a soft hand is preferred.

A compromise between the properties imparted by the urea-formaldehyde and melamine-formaldehyde resin types is ofiered by the water-soluble ethylene urea-formaldehyde resin type. This resin type imparts substantially the same wrinkle recovery obtained by certain melamineformaldehyde type resins at the same low resin concen- More particularly, it relates to. the treatment of trations without the disadvantage of discol-oring as a result of chlorine retention. However, ethylene urea type resins cause tensile strength losses intermediate to those produced by urea and melamineformaldehyde type resins when scorched followed by chlorine bleaching. In addition, its durability to usual washing and bleaching operations is intermediate to the urea and melamine-formaldehyde type resins.

Thus, in general, melamine-formaldehyde resins are preferred for many applications, and the number of such preferred applications would be increased, particularly on white fabric, but for the discoloration resulting from chlorine retention.

Therefore, it is an object of the present invention to provide a process for treating cellulosic textile materials to crease proof the same with a unique essentially monomeric melamine-formaldehyde resin which is not normally Water-soluble.

It is a still further object to provide a process for treating cellulosic textile materials to crease proof the same with such melamine-formaldehyde resins, which process substantially eliminates discoloration due to chlorine retention (from chlorine bleaching) normally experienced with some water-soluble melamine resins.

It is a further object to provide such a process which in addition imparts a surprisingly significantly softer hand to the textile fabric so finished.

It is a further and special aspect of this invention to provide a novel means for rendering the novel normally water-insoluble melamine-formaldehyde resins contemplated for use in this invention sufiiciently water-soluble by weight of the material of a melamine-formaldehyde condensate characterized by being normally waterinsoluble, substantially monomeric condensates and having the following general formula:

where n is a positive integer having an average value of between 5 and 6 inclusive and R may be an alkyl group containing 1 to 4 carbon atoms, and thereafter curing said melamine-formaldehyde condensate on the textile ma-- terial by the action of heat in the accelerator.

In accordance'with the present specification and claims, the term cellulosic textile material and similar expressions as they are employed herein, refer to formed textile materials whether they be knitted, felted, woven or otherwise formed, which contain a substantial portion of cellupresence of a curing losic fiber, an amount in excess of 50% thereof, as for.

example, cotton, cuprammonium and viscose rayon, linen, ute, hemp and other cellulosic materials. Such cellulosic materials and particularly cotton, preferably are the only fiber employed in the formed textile material. However, they may be employed in blends with synthetic or natural fiber materials, as for example, acetate fibers, nylon, the acrylic fibers, the polyester fibers, wool and the like.

By the expression normally water-insoluble as that term is applied herein, it is meant that the melamineformaldehyde condensates contemplated herein are incapable of simple solution in Water (solution by mere mixing in water) in amounts above trace amounts as for example 0.5%, based on the total weight of a solution at room temperature (25 C.) and their degree of solu- Fatentecl Feb. 1, 1966 bility cannot be increased by heating mixtures thereof in Water at temperatures up to the boiling point of water.

By the expressions substantially monomeric or essentially monomeric as these terms are employed referring to the melamine-formaldehyde condensates of this invention, it is meant that the condensates are in substantially monomeric form and are substantially free from the presence of polymer. Thus, in a given melamine-formaldehyde condensate contemplated for use in the present invention, minor amounts of dimers, trimers, and the like may be present, but the materials are in general characterized as being monomeric in form.

The normally water-insoluble, substantially monomeric melamine-formaldehyde condensates contemplated for use in the present invention have the following general formula:

wherein n is a positive integer having an average value of between and 6 inclusive, and R is an alkyl radical containing from 1 to 4 carbon atoms. These melamineformal-dehyde condensates of the present invention are melamine-formaldehyde condensates characterized by a methylol or formaldehyde substitution of between 5 and 6 methylol groups, which material has been further condensed with a lower alkyl alcohol, methanol, ethanol, propanol, and butanol.

In addition to these condensates being normally waterinsoluble, substantially monomeric materials, they are characterized in their unuseable form by being a white, wax-like composition. It should be noted that melamineformaldehyde condensates of this invention are waterinsoluble, not by virtue of the fact that the condensates are polymerized, for they are essentially monomeric, but by virtue of the fact that the high degree of substitution therein renders these materials normally water-insoluble.

As will be seen more clearly hereinafter, by a particular aspect of this invention, these resins are rendered water-soluble to a suflicient order of magnitude to permit their use in textile finishing.

Because of the fact that these melamine-formaldehyde condensates are normally water-insoluble, and therefore would not normally be considered for use in textile finishing, it is quite unexpected that their employment in textile finishing results in unexpected and improved properties for materials so treated therewith with respect to discoloration due to chlorine retention. Additionally, the results in the softening of the hand of materials so treated is unexpected. These properties are further surprising in that, in view of the physical nature of the melamineformaldehyde condensates contemplated, it is most surprising that they would even be considered for use in crease-proofing finishes for textile material.

These aspects of the present invention will be described and illustrated more clearly hereinafter.

The melamine-formaldehyde condensates contemplated for use in the present invention may be prepared by a number of procedures. One such procedure comprises heating with continuous mixing melamine and formaldehyde in mole ratios of from 1 to 6.5 to 1 to 20, and preferably from 1 to 6.5 and l to 10, respectively, in the presence of about 45 to 75% (preferably from 55 to 65%) by weight of water based on the total weight of the reaction mixture while maintaining a pH of between 7.0 and 8.5 (preferably from between 7.3 and 8.3) and a temperature of between 45 C. and 75 C. (preferably 55 to 65 C.) until the reaction mixture has cleared or has become transparent. Thereafter, the temperature of the reaction mixture should be maintained from between 45 and 75 C. (preferably 55 to 65 C.) while stirring the reaction mixture without agitation until a major portion of the precipitated product is formed, after which the reaction mixture is cooled to a temperature of between 15 and 30 C. until substantially all of the product has precipitated.

The precipitated product may then be readily separated from the reaction medium by filtration, centrifuging, or the like, after which it is dehydrated as by heating at 75 C. in a rotary tumble type drier or other suitable drier or drying means, so that it may be etherified. Dehydration to a water content of less than 20% and preferably to between 5 and 15% is necessary in order to achieve the high degree of etherification characteristic of the condensates employed in this invention.

As used herein, the term mixing is intended to include the function of mixing and/ or stirring means which are or are not accompanied by agitation. The term agitation in turn, is intended to include the concept of mixing so as to produce a turbulent or violent movement in the reaction mixture. Mixing or stirring with agitation using an anchor type of stirrer as an exemplary mixing means would involve the stirrer moving through the reaction mixture so as to produce violet movement therein. Mixing or stirring without agitation employing a similar stirring means would include the stirrer moving through the reaction mixture so as not to produce any violent movement therein, or to be simply passing through said mixture.

If the initial reactants are mixed with agitation, it is greatly preferred that when the reaction mixture clears, the speed of the mixing means is reduced so as to be mixing without agitation in order that the particles of methylol melamine be allowed to grow to sizes which are more readily handled by conventional solid separating means. If, when the reaction mixture clears, the said mixing means continues to mix with agitation, the product tends to precipitate from the solution more rapidly and in a much more finely divided state, which renders it more diflicult to handle. Mixing without agitation may be employed throughout the present process. In such an instance, the process is more time-consuming without resulting in an improved product.

If the preferred procedure described above is employed, it is not absolutely essential to the present invention that the mixing means be adjusted so as to be mixing without agitation precisely at the moment the reaction mixture clears. While best results are achieved when the mixing means are adjusted very shortly after the clearing of the reaction mixture, such adjustments have been made with an acceptable product produced, even after the precipitated product begins to form.

To etherify the methylol melamine produced as set forth hereinabove, a mole ratio of 1 mole of said melamine-formaldehyde reaction product, dehydrated to a water content of less than 20%, and between 10 and 16 moles and preferably between 12 and 15 moles of a suitable saturated aliphatic alcohol compound, are reacted at a temperature of between 15 and 60 C. and a pH of less than 3 until complete solution of the reactants is obtained. At this point, the pH is adjusted to from between 8 and 10 with an alkali such as caustic, potassium, hydroxide, sodium bicarbonate, or other compatible basic materials, and thereafter the solution is vacuum concentrated until a viscous syrup is formed which is sub stantially free of unreacted alcohol and water. Upon cooling, a sol-id product formed.

The resulting resin is solvent soluble as for example in xylene, benzene, and the like, but is normally waterinsoluble within the definition of that term set forth above.

In order for these resins to be employed as creaseproofing resins, they must be rendered sufiiciently watersoluble to permit such use. By sufi'iciently water-soluble it is meant that the resin must be capable of entering into aqueous solution in practical concentrations, as for example, 15 to 35% solids by weight or more, based on the total weight of solution, such amounts being sufi"1 cient to permit commercial operating conditions to be employed and to readily permit the application of high solids to the textile material where this is desired. High solids for crease-proofing resins are considered as being amounts between 10 and 25% solids based on the dry Weight of the textile material.

Suitable etherifying agents within the meaning of this invention include methyl, ethyl, propyl, isopropyl, isotbutyl and butyl alcohols. For purposes of the present invention, methyl alcohol is greatly preferred because cost of the final product is lessened and the degree of water solubility essential is more readily achieved.

In accordance with this invention, we have found that the resinous products contemplated for use herein may be rendered sufiiciently water soluble by different methods. In one of these, the wax-like solid may be pulverized and the wax-like powder added to a high speed blending device and stirring or blending effected while maintaining the temperature at from between and C. In order to insure maintenance of the temperature within this narrow range, the container may be placed periodically in an ice bath. When no more of the resin which is periodically added appears to dissolve, the contents of the container may be filtered and the solution analyzed for nitrogen, from which value the amount of resin in the solution can be calculated.

By such a procedure, a solution of up to 35% solids of the resin contemplated by this invention may be prepared, but normally several hours are required, which enters a practical limitation on such a procedure. Further, regardless of the concentration of the solids prepared, some undissolved material will be found after completion of the stirring in the high speed blending apparatus, so that filtration and solution analysis is always required in order to determine the true resin concentration in solution.

A much simpler and greatly preferred method of effecting the solution involves the weighing out of the desired amount of resin solids, adding thereto the desired amount of water for a given application run, the water having a temperature higher than the melting point of the resin or heated to this temperature in the presence of the resin (preferably at least 5 C. higher and usually to C.),and containing from between 0.1 and 1% of a non-ionic wetting agent. This reaction mixture is then stirred, although high speed stirring devices of the type contemplated in the procedure above are unnecessary and possibly even undesirable. Thereafter, this mixture is cooled to room temperature with occasional stirring, at which time complete solution is effected. Solutions of up to 35% resin solids concentration and somewhat higher can be readily effected in this manner and require only minutes, further eliminating the need for filtration and solution analysis to determine true resin concentration.

In principle, it appears that the hot Water which is added, functions to melt the resin, giving the system two liquid phases. The wetting action of the non-ionic agent affects a mixing of the two phases and immediate com.- plete solution is effected upon cooling.

Conveniently, only a portion of the water required for the desired solution may be added at the required temperature to effect melting of the resin. Then additional water containing the non-ionic agent, and having a lower temperature, may be added to give the desired amount of water for the ultimate solution. The nonionic agent may be added to the high temperature Water portion Without effecting the result.

Normally, the condensates contemplated by this invention will have melting points as determined by the Parr Bar method of significantly less than the boiling point of water at atmospheric pressure, and thus the process is readily carried out in conventional equipment. In general, condensates contemplated by this invention will have melting points under 90 C.

Non-ionic agents are preferred as wetting agents since the catalyst employed to cure the resin may otherwise precipitate the ionic types. The class of non-ionic agents preferred are given by the following general formula:

where n is an integer from about 3 to 10 and higher, and R is alkyl containing from (1 to 10 carbon atoms and preferably 8 to 9.

Typical products successfully employed are the reaction products of octyl phenol and ethylene oxide (12:6), the type known as Triton X400, the reaction products of nonyl phenol and ethylene oxide (12:9) and others.

As noted above, it is Well known that textile materials may be treated with certain melamine-formaldehyde reaction products including methylated melamine-formaldehyde reaction products and that such treatment imparts increased stiffness to treated textile materials, while effecting shrinkage control and wrinkle recovery or crease proofing. This property is characteristic of the resin type and is generally morepronounced as the degree of methylolation and etherifica-tion is increased. With this as background, it therefore might reasonably be predicted that the resins contemplated by this invention would impart increased firmness to the treated fabric, as

compared with lesser substituted resins, as for example, a trimethylated trimethylol melamine. In surprising distinction, however, the hand of fabric treated with resins contemplated by this invention are extremely soft, even softer than the untreated fabric, a fact wholly unexpected and contrary to predictions of those skilled in the art.

The most important characteristic of the resinous product contemplated for use in this invention, which would be unpredictable based on the knowledge and performance of methylated methylol melamine textile resins is that in the application of these resins, the tendency of textile fabrics and particularly white fabrics to discolor when subject to the action of chlorine bleaching, is substantially overcome. The fabrics treated with the product of the process set forth hereinabove. When chlorine bleached exhibit substantially no discoloration, even when subjected to a large number of bleachin cycles.

It has been found that the improved. properties recited hereinabove may be imparted to textile fabrics by treating them with the resins contemplated by this invention and a suitable curing catalyst or accelerator followed by subsequent drying and curing.

The resins may be applied by conventional finishing methods, such as immersion, padding, spraying, and the like and followed, where necessary, by squeezing, hydroextraction, or similar processes, in order to atiix the desired amount of resin solids onto the fabric.

The method of application should be such that from about 1 to about 25% and, in some instances, higher amounts of the resins based on the Weight of the fabric, is deposited on the textile material. Within certain limits, the amount applied depends upon the particular type of textile being treated. Thus, when treating fabrics consisting of cellulosic fibrous material and particularly cotton, the concentration of the order of from about 1 to about 25%, and more, particularly from between about 3 and about 10% resin solids, based on the weight of the dried fabric is employed.

The catalyst or accelerator utilized may consist of the type comprising free acid, alkanolamine salts, metal salts, and the like. The concentration of catalyst employed may range from between about 0.1 to about 25% or higher, based on the weight of resin solids, depending upon the particular catalyst type employed. Thus, for example, from between about 0.1 and about 10% of a free acid such as phosphoric, tartaric, oxalic, or the like, may be employed, while in the case of ammonium chloride, amounts of between about 0.5 and about 10% are used. In the case of amine salts, including alkanolamine salts, from about 1.0 to about 10% are most useful, while with respect to salts such as magnesium chloride, zinc chloride and the like, amounts of between about and about 25% have been successfully employed. In all instances, the concentration of catalyst is based on the weight of resin solids employed.

Following the application of the resin and curing catalyst to the textile fabric, the material is subject to the drying and curing operation to effect desired improving properties. The drying and curing operations may be carried out in a single step or in separate steps. The temperatures at which drying and curing operations are effected vary widely and are influenced, to some extent, by the type of catalyst employed. Normally, the range of temperature extends from about 180 F. to about 450 F. and even higher. Generally speaking, the time of the drying and/ or curing operation is inversely proportional to the temperature employed and, of course, is influenced by whether or not separate or combined drying and curing steps are employed.

Generally, when drying and curing is carried out in a combined operation, a time from about 1 minute to minutes may be employed at temperatures from about 450 F. to 250 F., respectively. When the fabric has been dried, preliminary to curing, curing times of the order of from 5 minutes to about A minute, at temperatures of from between 250 F. and 450 F. respectively, have been successfully employed.

The following examples are given primarily by way of illustration so that the present invention may be more fully understood. No details therein should be construed as limitations on the present invention except as they appear in the appended claims. All parts and percentages are by weight unless otherwise designated.

EXAMPLE 1 Into a suitable reaction vessel 386 parts (4.76 moles) of a formalin (37% formaldehyde) solution was charged and the pH of the reaction mixture adjusted to between 7.4 and 7.5 with sodium bicarbonate. The formaldehyde solution was then heated to between 55 and 60 C. and 80 parts (0.635 mole) of melamine were charged and mixed with vigorous agitation. The mole ratio of melamine to formaldehyde was 1275. During solution of the melamine, the pH was found to increase to between 8.2 and 8.5 as a result of the reaction taking place. The amount of water was about 52% based on the total weight of the reaction mixture.

When the solids had gone into solution, the speed of the mixing means was greatly reduced, but sufficient to provide a low degree of mixing with little or no agitation or turbulence. The temperature of the reaction mixture was held at between 60 and 65 C. for one hour under these conditions of mixing, during which period, better than 60% of the solid methylol melamine reaction product was precipitated from the reaction mixture. After the one-hour period, cooling was initiated such that the cooling rate did not exceed C. per hour. Mixing without agitation was employed during this period.

During the cooling cycle, additional water was added as required by the apparent viscosity of slurry to adjust the water content from 52% to a content of 65% based on the total weight of the reaction mixture.

After cooling to 30 C. the solids were washed with water on an Oliver rotary vacuum filter, removing approximately 80% of residual formaldehyde from the product. The washed cake was then dried at 50 C. until substantially dry to the feel. The product contained about 5% free moisture, and had a melting point of 108 C. A yield of better than 90% was realized.

8 EXAMPLE 2 Three hundred and thirty parts of the methylol melamine prepared according to Example 1, 320 parts of methanol, and 10 parts of concentrated sulfuric acid sufficient to adjust the pH to between 1 and 1.5 were charged into a suitable reaction vessel. The mole ratio between the methanol and the methylol melamine was 10: 1, respectively. Stirring of the reactants was continued until a slightly hazy solution was obtained. This was achieved in about one hour, and then the pH of the reaction mixture was adjusted to 8 with alkali. After this adjustment, the water and excess alcohol were distilled off in vacuo keeping the temperature below 50 C. The residue was filtered to yield a clear water-white product which upon cooling formed a solid. The yield was about EXAMPLE 3 Twenty-five parts of the reaction product produced according to the process set forth in Example 2 were ground with a mortar and pestle to a fine particle size and added to a Waring blender. Seventy-five parts of ice water (0 C.) were added to the mixture and it was allowed to stir for approximately 10 minutes. At this time, the temperature of the mixture had risen, both because of a higher surrounding atmospheric temperature, and because of the heat generated by the stirring action of the blender. The container of the blender was therefore removed and cooled in an ice bath to a temperature of 0 C. The container was replaced on the blender and stirring continued until solution was completed. At no time did the temperature of the stirred mixture rise above 25 C. A total stirring time of about 45 minutes was sufficient to effect complete solution. The solution obtained contained 25 solids of the reaction product made according to Example 2 and may be diluted to lower solids readily with water.

EXAMPLE 4 Into a suitable reaction vessel 25 parts of the reaction product produced according to Example 2, 0.33 part of Deceresol NI (reaction product of nonylphenol and 9 moles of ethylene oxide) and 40 parts of water at 60 C. were charged. The above ingredients were mixed in a beaker with stirring until the solid ingredients had been completely melted, which required about 10 minutes. To this mixture, which is an unhomogeneous liquid of two phases, was added 34.67 :parts of ice water at 0 C. A stable solution resulted.

In the following table, all of the fabric was padded through pad baths containing the resins and catalysts re- :ferred to therein and then treated on a microset padder set at 18 pounds per square inch to thereby obtain a wet pick-up of approximately 85%. The amount of resin applied to the fabric was 5% resin solids based on the fabrics weight and amount of catalyst was 18% based on the weight of the resin solids. The treated fabrics were dried two minutes at 225 F. and cured for 1.5 minutes at 350 F. unless otherwise stated. Fabrics being tested for shrinkage control determinations were dried and framed to size. All others were dried in the relaxed condition.

The washes referred to in the following tables consisted of a 15-minute wash cycle of F. in a solution containing 0.01% soap and 0.02% available chlorine (Clorox) at a liquid to cloth ratio of 7 to 1 in a Laundromat washer. Following bleaching, the fabrics were rinsed in water at 140 F. for three five-minute cycles and then tumble dried at from 140 to F. for thirty minutes.

The various physical properties which are reported in the following tables were determined in accordance with the procedure described in the 1955 Technical Manual and Yearbook of the American Association of Textile Chemists and Colorists, volume 31.

The scorched tensile strength values were determined on fabrics bleached by the procedure described hereinabove, but scorched in accordance with tentative test method 6942, described on pages 60 and 61 of the above cited reference. The percentage of strength loss is calculated from the initial and bleached scorch values as described in the reference.

Reflectance values for determination of color were run on a recording spectrophotometer using a magnesium carbonate block as a reference standard.

Comparison of properties of treated fabrics Cotton percale, 80" x 80", was impregnated in the general manner described hereinabove with each of the following baths:

TABLE 1 A B O D Reaction product of Example 2 (100% solids 58. 8 Methylated trimethylol melamine (80%) 73. 5 Dimethylol ethylene urea (50%). 117. 5 Dimethylol urea (60%) 98.0 Magnesium chloride (anhydrous) 10. 6 10. 6 10.6 10.6 Water to 1,000 1, 000 1, 000 1, 000 Wet pick-up, percent 85 M Percent solids on fabric 5 5 5 5 Percent magnesium chloride on resin solids 18 18 18 18 Untreated Reflectance (percent at 450 Initial 87 85 85 85 85 After 25 Laundromat washes with Clorox 87 85 56 86 86 Strength loss (lue to scorching), percent 8 U 40 80 Available chlorine on fabric percent: Initial 0 0 0 0 0 25 Laundromat washes with Clorox 0 1. 33 0. 25 0. 86 1. 44 Hand (Initial) 1 Solution effected as in Example 3. Standard.

3 Soitest (softer than Std).

4 Firm.

5 Soft as Std.

Table 1 hereinabove clearly demonstrates that finishing cellulose textile fabric with the normally water-insoluble, essentially monomeric resins of this invention results in substantially no discoloration due to chlorine retention and a definitely softer hand.

These textile treating compositions possess a wide variety of desirable features. They may be employed with other textile finishing resins, either thermosetting or thermoplastic, to improve the durability of such finishes. In addition, the alkylated melamine-formaldehyde reaction product may be employed with softeners, stifieners, lubricants, dicyandiamide, and other conventional treating bath components.

What is claimed is:

1. A process for rendering solid, normally water-soluble, essentially monomeric melamine-formaldehyde condensates characterized by the following general formula:

Where It is a positive integer having an average value between 5 and 6, inclusive, and R is an alkyl group containing 1 to 4 carbon atoms, sufliciently Water-soluble, to be em-ployable commercially as textile crease proofing resins which comprises melting the solid condensate with Water having a temperature at least about 10 C. higher than the melting point of the condensate, to form two liquid phases, and effecting solution by cooling the two phases in the presence of a non-ionic surface active agent.

2. A process according to claim 1, in which the aqueous solution contains from between 15 and about 35% resin solids.

3. A process according to claim 1, in which the liquid phases are cooled to between 0 and 15 C. to effect solution.

References Cited by the Examiner UNITED STATES PATENTS 2,981,704 4/1961 Herbes et a1. 260--29.4 3,087,837 4/1963 Van Loo et al 1l7139.4

MURRAY TILLMAN, Primary Examiner.

LEON J. BERCOVITZ, Examiner.

Dedication 3,232,898. William J. Van Loo, Jr., Middlesex, N.J., and Jason M Salsbury,

Stamford, Conn. PROCESS FOR RENDERING WATER-INSOLU- BLE MELAMINE-FORMALDEHYDE RESINS WATER-SOLU- BLE. Patent dated Feb. 1, 1966. Dedication filed Mar. 4, 1983, by the assignee, American Cyanamia' C0. Hereby dedicates the remaining term of said patent to the Public.

[Oflicial Gazette May 31, 1983.] 

1. A PROCESS FOR RENDERING SOLID, NORMALLY WATER-SOLUBLE, ESSENTIALLY MONOMERIC MELAMINE FORMALDEHYDE CONDENSATES CHARACTERIZED BY THE FOLLOWING GENERAL FORMULA: 